Infection with Hepatitis B virus (HBV) is still a serious public health problem, with an estimated 300 million chronic carriers worldwide. In recent years, substantial progress has been made in establishing the molecular basis of individual steps in the replication of the virus, revealing its unique status among retroelements. However, immense experimental difficulties, including the lack of appropriate in vivo and experimental, infection systems, have hampered a similarly detailed analysis of the early steps of infection. The limitations have further hindered the fundamental understanding the complex interplay between virus and host and its effects on pathogenicity. This conference is distinct from clinically oriented meetings, and is intended to gather scientists studying different aspects of HBV and related animal model viruses, for joint discussion of the latest conceptual and technical advances. The meeting is organized by Drs. Betty Slagle and Michael Roggendorf, who are assisted by a panel of expert HBV scientists acting as chairpersons for 12 lecture and 2 poster sessions. In addition, it is planned to have a workshop on controversial issues. Session topics will include: transcription; replication; structural proteins and receptors; regulatory proteins; hepatocellular carcinoma; HBV variants and hepatitis delta virus; and persistence, pathogenesis, and immunology. Each session will comprise 4-8 talks, selected from submitted abstracts that are peer-reviewed by the session chairpersons. In the tradition of previous meetings of this series, in addition to the attendance and presentations by senior investigators, graduate students and postdoctoral fellows will be particularly encouraged to participate in the lecture and poster sessions. HBV research is a major topic in the research mission of NIAID, and this is the only annual HBV meeting of its kind.